A. Field of the Invention
The present invention relates to a new and improved fastener tool with a single control that may be adjusted to place the tool in a single shot sequential fire mode or a multi-shot sequential fire mode.
B. Description of the Background Art
There are fastener driving tools available with control systems that allow touch trip firing. Touch trip firing allows the tool to be fired either by depressing the safety first and then the trigger or the trigger first followed by depressing the safety.
For safety purposes many fastener driving tools include a sequential fire control requiring the safety of the tool to be actuated by first placing the tool against a workpiece. Once the safety is actuated, a trigger may be actuated to fire the tool.
More stapling and nailing equipment users are requiring sequential fire controls to be provided on fastener driving tools. Some of the users with the strictest standards require both the trigger and the safety to be released each time the tool is to be fired. This mode of operation is designated the single-shot, sequential fire mode. Tool operation in this mode increases the time required to place a given number of fasteners in a workpiece.
There are other applications, however, in which safe operation is achieved by keeping the nose of the tool against the workpiece and cyclically actuating and releasing the trigger. This latter mode is termed the multi-shot sequential fire mode.
There is a distinct advantage, both from the viewpoint of manufacturing and inventory requirements, to be able to achieve both of these modes of operation with a single tool or single tool control.
A basic fastener driving tool with a trigger control valve, a safety control valve and a cycling valve is disclosed in U.S. Pat. No. 3,638,532. This tool with a manual control for selecting single or multiple cycles of operations is disclosed in U.S. Pat. No. 3,547,003. Sequential fire control, either solely pneumatic or pneumatic and mechanical is disclosed in U.S. Pat. No. 3,677,457 (combined mechanical -pneumatic control) and U.S. Pat. No. 3,677,456 (an all pneumatic arrangement).
None of the tools disclosed in these patents includes a single control that can be easily adjusted between the single shot and multi-shot, sequential modes of operation. Such an adjustment feature is of significant value since it allows the manufacturer to easily adjust each tool to the specific mode of fire control desired by the purchaser.